Systems and Methods for Unmanned Aerial Vehicle Navigation

ABSTRACT

Systems and methods for unmanned aerial vehicle (UAV) navigation are presented. In a preferred embodiment, a UAV is configured with at least one flight corridor and flight path, and a first UAV flight plan is calculated. During operation of the first UAV flight plan, the UAV visually detects an obstacle, and calculates a second UAV flight plan to avoid the obstacle. Furthermore, during operation of either the first or the second UAV flight plan, the UAV acoustically detects an unknown aircraft, and calculates a third UAV flight plan to avoid the unknown aircraft. Additionally, the UAV may calculate a new flight plan based on other input, such as information received from a ground control station.

GOVERNMENT RIGHTS

The United States Government may have acquired certain rights in thisinvention pursuant to Contract No. W56 HZV-05-C-0724 with the UnitedStates Army.

FIELD

The embodiments herein relate to systems and methods for navigation ofunmanned aerial vehicles (UAVs).

BACKGROUND

A UAV is a remotely piloted or self-piloted aircraft that can carrycameras, sensors, communications equipment, or other payloads, iscapable of controlled, sustained, level flight, and is usually poweredby an engine. A self-piloted UAV may fly autonomously based onpre-programmed flight plans.

UAVs are becoming increasingly used for various missions where mannedflight vehicles are not appropriate or not feasible. These missions mayinclude military situations, such as surveillance, reconnaissance,target acquisition, data acquisition, communications relay, decoy,harassment, or supply flights. UAVs are also used for a growing numberof civilian missions where a human observer would be at risk, such asfirefighting, natural disaster reconnaissance, police observation ofcivil disturbances or crime scenes, and scientific research. An exampleof the latter would be observation of weather formations or of avolcano.

As miniaturization technology has improved, it is now possible tomanufacture very small UAVs (sometimes referred to as micro-aerialvehicles, or MAVs). For examples of UAV and MAV design and operation,see U.S. patent application Ser. Nos. 11/752,497, 11/753,017, and12/187,172, all of which are hereby incorporated by reference in theirentirety herein.

A UAV can be designed to use a ducted fan for propulsion, and may flylike a helicopter, using a propeller that draws in air through a duct toprovide lift. The UAV propeller is preferably enclosed in the duct andis generally driven by a gasoline engine. The UAV may be controlledusing micro-electrical mechanical systems (MEMS) electronic sensortechnology.

Traditional aircraft may utilize a dihedral wing design, in which thewings exhibit an upward angle from lengthwise axis of the aircraft whenthe wings are viewed from the front or rear of this axis. A ducted fanUAV may lack a dihedral wing design and, therefore, it may bechallenging to determine which direction a ducted fan UAV is flying.Consequently, it can be difficult for both manned and unmanned vehiclesto avoid collisions with such a UAV. As UAVs are more widely deployed,the airspace will become more crowded. Thus, there is an increasing needto improve UAV collision avoidance systems.

SUMMARY

In order to improve UAV navigation, a UAV may be configured with datarepresenting at least one flight corridor and at least one flight path.A first flight plan may be calculated to avoid the flight corridor andthe flight path by navigating around, over or under the locations ofthese items. During the course of the UAV's operation of the firstflight plan, the UAV may detect, for example via a camera, an obstaclewithin the UAV's flight plan or in the vicinity of the UAV's flightplan. Consequently, a second flight plan may be calculated to avoid theobstacle as well as flight corridors and flight paths.

In a further embodiment, the UAV may also use acoustic input to detectnearby unknown aircraft and respond by calculating a new flight plan toavoid the detected unknown aircraft. Additionally, the UAV may receivetransmissions from a friendly UAV or manned vehicle that indicate thelocation and/or vector of an obstacle. The UAV may respond bycalculating a new flight plan to avoid the obstacle. These UAVnavigation mechanisms may be performed autonomously by the UAV or inconjunction with input from one or more ground control stations.

In general, the UAV may utilize multiple input modes (e.g., manual,optical, acoustic, thermal, and/or electronic means) to make flight plancalculations and adjustments. This multi-modal navigation logic may bepre-configured in the UAV, or may be dynamically uploaded to the UAV.

These and other aspects and advantages will become apparent to those ofordinary skill in the art by reading the following detailed description,with reference where appropriate to the accompanying drawings. Further,it should be understood that the foregoing overview is merely exemplaryand is not intended to limit the scope of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an example UAV design;

FIG. 2 depicts an example of a UAV flight plan that avoids interferencewith various ground-based and aerial objects and obstacles;

FIG. 3 depicts an example of a UAV detecting and avoiding an unknownaircraft;

FIG. 4 depicts an example of a UAV calculating a new flight plan basedon input from a friendly UAV;

FIGS. 5, 6, and 7 are flow charts of methods in accordance with exampleembodiments; and

FIG. 8 is a block diagram depicting functional units that comprise anexample UAV.

DESCRIPTION

FIG. 1 depicts an example UAV 100. UAV 100 may be used forreconnaissance, surveillance and target acquisition (RSTA) missions. Forexample, UAV 100 may launch and execute an RSTA mission by flying to oneor more waypoints according to a flight plan before arriving at alanding position. Once launched, UAV 100 can perform such a UAV flightplan autonomously or with varying degrees of remote operator guidancefrom one or more ground control stations. UAV 100 may be a hoveringducted fan UAV, but alternative UAV embodiments can also be used.

UAV 100 may include one or more active or passive sensors, such as avideo camera or an acoustic sensor. In alternative embodiments,different types of sensors may be used in addition to the video cameraand/or the acoustic sensor, such as motion sensors, heat sensors, windsensors, RADAR, LADAR, electro-optical (EO), non-visible-light sensors(e.g. infrared (IR) sensors), and/or EO/IR sensors. Furthermore,multiple types of sensors may be utilized in conjunction with oneanother in accordance with multi-modal navigation logic. Different typesof sensors may be used depending on the characteristics of the intendedUAV mission and the environment in which the UAV is expected to operate.

UAV 100 may also comprise a processor and a memory coupled to thesesensors and other input devices. The memory is preferably configured tocontain static and/or dynamic data, including the UAV's flight plan,flight corridors, flight paths, terrain maps, and other navigationalinformation. The memory may also contain program instructions,executable by the processor, to conduct flight operations, and otheroperations, in accordance with the methods disclosed herein.

Generally speaking, UAV 100 may be programmed with a UAV flight planthat instructs UAV 100 to fly between a number of waypoints in aparticular order, while avoiding certain geographical coordinates,locations, or obstacles. For example, if UAV 100 is flying in thevicinity of a commercial, civilian or military flight corridor, UAV 100should avoid flying in this corridor during the flight corridor's hoursof operation. Similarly, if UAV 100 is programmed with a flight path ofa manned aircraft or another UAV, UAV 100 should adjust its UAV flightplan avoid this flight path. Additionally, if UAV 100 is flyingaccording to its UAV flight plan and UAV 100 encounters a known orpreviously unknown obstacle, UAV 100 should adjust its UAV flight planto avoid the obstacle.

Herein, the term “flight plan” generally refers to the planned path offlight of a UAV, such as UAV 100, while the term “flight path” generallyrefers to an observed or planned path of flight of another aerialvehicle that the UAV may encounter. However, these terms may otherwisebe used interchangeably.

FIG. 2 depicts a UAV flight according to a UAV flight plan, where theUAV, for example UAV 100, calculates the UAV flight plan in order toavoid a flight corridor and another aircraft's flight path. In doing so,the UAV preferably makes use of multi-modal logic and input from atleast two sources. The UAV flight plan may later be adjusted (or a newflight plan may be calculated) to avoid an obstacle. This adjustment orrecalculation also preferably uses multi-modal logic.

The UAV flight plan depicted in FIG. 2 includes four waypoints. It isassumed that UAV 100 begins at waypoint 210, proceeds to waypoint 215,then to waypoint 220, and finally to waypoint 225 before returning towaypoint 210. However, these four waypoints and this UAV flight plan aremerely examples. An actual UAV flight plan may contain more or fewerwaypoints, and the paths between these waypoints may be more or lessdirect than is depicted in FIG. 2.

UAV 100 may comprise an on-board global positioning system (GPS) fordetermining its location and velocity, and for adjusting its UAV flightplan. However, UAV 100 may use other types of position-determiningequipment instead of or along with a GPS in order to navigate.

Presumably, UAV 100 is pre-configured with information regarding airport230, flight corridor 245 and flight path 235. Alternatively, thisinformation may be uploaded to UAV 100 during flight planning ordynamically transmitted to UAV 100 during flight. UAV 100 may not,however, contain information regarding obstacle 240. Thus, UAV 100 maybe able to calculate a first UAV flight plan that avoids airport 230,flight corridor 245 and flight path 235, but UAV 100 may need todynamically adjust its UAV flight plan to avoid obstacle 240.

For example, based on the first UAV flight plan and input from one ormore of its sensors, UAV 100 may calculate a second UAV flight plan toavoid obstacle 240. Alternatively, UAV 100 may dynamically adjust orrecalculate its UAV flight plan to avoid airport 230, flight corridor245, flight path 235 and obstacle 240. Furthermore, UAV 100 may adjustits UAV flight plan based on input from a ground control station aswell.

Regardless of exactly how UAV 100 is arranged to operate, adjust, orrecalculate its UAV flight plan, when UAV 100 reaches point A, UAV 100determines that it needs to avoid flight corridor 245. A flightcorridor, or airway, is typically airspace that military, commercial, orcivilian aircraft may use. A flight corridor may be thought of as athree dimensional highway above the ground in which aircraft may fly.These aircraft may or may not be under directions from a control towerwhile in the flight corridor. A flight corridor is preferably specifiedby a vector, a width, one or more altitudes or a range of altitudes, anda range of time. For example, flight corridor 245 might be specified bya vector of 305 degrees, a width of 10 nautical miles, a range ofaltitudes from 0 (zero) to 10,000 feet, and a range of time from 06:00hours to 14:00 hours (6 AM to 2 PM). However, a flight corridor can bespecified using more or fewer factors.

The range of time preferably specifies the hours of the day during whichflight corridor 245 will be in use. Presumably, flight corridor 245 willnot be used by any aircraft outside of this range of hours, andtherefore UAV 100 could safely intersect flight corridor 245 outside ofthis range of hours.

When approaching point A, UAV 100 determines that it is about tointersect flight corridor 245. Preferably, UAV 100 compares the currenttime to the range of time for flight corridor 245. If the current timeis within the range of time for flight corridor 245, UAV 100 determinesthat it should avoid flight corridor 245. As depicted in FIG. 2, UAV 100may fly around flight corridor 245 and nearby airport 230.Alternatively, UAV 100 may determine that it can change altitude toavoid flight corridor 245. Preferably, UAV avoids flight corridor 245and airport 230 by some number of nautical miles, or by some thousandsof feet in altitude.

At point B, UAV 100 has passed flight corridor 245 and airport 230, andhas re-acquired its original vector towards waypoint 215. However, UAV100 need not re-acquire this vector, and may proceed to waypoint 215 ina more direct fashion.

Once at waypoint 215, UAV 100 changes direction and proceeds, accordingto its UAV flight plan, on a vector towards waypoint 220. At point C,UAV 100 determines that it may intersect flight path 235. Flight path235 may be a pre-determined flight path of another UAV or a mannedaircraft. Preferably, UAV 100 maintains its vector but changes altitudebetween point C and point D in order to avoid an aircraft flyingaccording to flight path 235. However, UAV 100 may avoid flight path 235in other ways.

At point D, UAV reverts to its previous altitude and proceeds accordingto its UAV flight plan to waypoint 220. Once at waypoint 220, UAV 100changes direction and proceeds, according to its UAV flight plan, on avector towards waypoint 225. At point E, UAV 100 senses obstacle 240.Obstacle 240 may have been previously unknown to UAV 100, and thereforeUAV 100 may dynamically adjust its UAV flight plan to avoid obstacle240. This adjustment may be autonomously determined and executed by UAV100, or may be made in conjunction with input from the ground controlstation.

Furthermore, obstacle 240 may be a stationary object, or may be anobject that is in motion either on the ground or in the air. Forexample, obstacle 240 might be an aircraft or a weather balloon.Alternatively, obstacle 240 may be a ground-based object, such as abuilding or a deployment of anti-aircraft artillery. Preferably UAV 100detects obstacle 240 with its onboard video camera, but UAV 100 may useone or more other sensors to detect obstacle 240.

At point E, UAV 100 dynamically adjusts its UAV flight plan to avoidobstacle 240. For example, UAV 100 may fly around, over or underobstacle 240. At point F, UAV 100 re-acquires its original vectortowards waypoint 225. Once at waypoint 225, UAV 100 changes directionand proceeds, according to its UAV flight plan, on a vector back towaypoint 210.

When, during, or after UAV 100 determines that it needs to change coursefor any reason, UAV 100 may transmit an alert to the ground controlstation indicating the course change. As part of this course change, UAV100 may use its sensors, for example a video camera, to acquire newimages of the nearby terrain. Thus, any of the maneuvers conducted byUAV 100 at point A, B, C, D, E, and/or F may be accompanied bycommunication between UAV 100 and a ground control station, as well asUAV 100 acquiring new images of nearby terrain.

In addition to avoiding flight corridors, flight paths and obstacles,UAV 100 may be configured to dynamically avoid unknown aircraft. Anunknown aircraft might approach UAV 100 from such an angle that UAV 100may be unable to detect the unknown aircraft with its video camera, orthrough other optical sensors. In order to detect unknown aircraft thatmight not be detected by the video camera or optical sensors, UAV 100may be equipped with an acoustic sensor. Such an acoustic sensor ispreferably capable of detecting engine noise and/or wind displacementnoise associated with such an unknown aircraft.

The acoustic sensor may include one or more acoustic probes, and adigital signal processor. Preferably, the acoustic probes are configuredto receive acoustic input signals and to remove noises associated windand UAV vibration from these signals. Furthermore, the acoustic inputsignals may be converted into electrical form and represented digitally.The digital signal processor may filter the acoustic input signals todetect and/or track nearby aircraft, and may provide navigational inputto other UAV components, such as the processor, so that UAV 100 mayavoid the detected aircraft and/or maintain a safe distance from thedetected aircraft. However, other types of acoustic or non-acousticsensors may be used for this purpose.

FIG. 3 depicts an exemplary embodiment of a UAV, such as UAV 100, usingacoustic sensor input to avoid an unknown aircraft. UAV 100 is flyingaccording to UAV flight plan 310. At point G, UAV 100 detects unknownaircraft 320. UAV 100 may determine or estimate that unknown aircraft320 is flying according to unknown aircraft vector 330. UAV 100 may thenadjust its flight plan to avoid unknown aircraft 320. Preferably, UAV100 detects unknown aircraft 320 via its acoustic sensors, but UAV 100may take similar evasive measures in response to other types of input,such as EO or IR signals.

Furthermore, UAV 100 may communicate with other friendly UAVs, friendlymanned aircraft, or ground control stations within its theater ofoperation in order to gather more information about its surroundings.For example, UAV 100 may receive information from a friendly UAV, mannedaircraft, or ground control station about a previously unknown flightcorridor, flight plan, flight path, obstacle, or another type ofsituational information, and UAV 100 may adjust its UAV flight planaccordingly. Additionally, UAV 100 may receive information from afriendly UAV, manned aircraft, or ground control station about anunknown aircraft in the vicinity and UAV 100 may adjust its flight planto avoid the unknown aircraft. Preferably, UAV 100 will use anynavigational input that it receives via any trusted source to determine,based on its mission's parameters, whether to make a dynamic change inits UAV flight plan.

FIG. 4 depicts a UAV, such as UAV 100, receiving input from a friendlyUAV, and adjusting its UAV flight plan according to this input.Alternatively, UAV 100 may receive this input from a friendly mannedaerial vehicle or a ground control station.

In FIG. 4, UAV 100 preferably flies according to UAV flight plan 410. Atpoint H, UAV 100 receives input from friendly UAV 420. Preferably, UAV100 receives this input via communication link 430, which may be awireless communication link. Communication link 430 may operateaccording to various types of wireless technologies, includingorthogonal frequency division multiplexing (OFDM), frequency hopping, orcode division multiple access (CDMA). Preferably, communication link 430is encrypted so that unauthorized listeners cannot decode transmissionsbetween UAV 100 and friendly UAV 420. Furthermore, UAV 100 and friendlyUAV 430 may communicate via point to point transmission transmissionsdirected to one another or via a broadcast system wherein other friendlyUAVs (not shown) may also receive transmissions between UAV 100 andfriendly UAV 420.

In response to receiving input from UAV 430, UAV 100 may adjust its UAVflight plan to take this input into account. For example, UAV 100 maycalculate a new flight plan to avoid a flight corridor, flight path,obstacle, or unknown aircraft in its path. Additionally, UAV 100 maystore the input received from friendly UAV 430 and later transmit thisinformation to another friendly UAV over a communication link.

The methods, systems, and devices disclosed in FIGS. 2, 3, and 4 may becombined, in whole or part, with one another. For example, UAV 100 maybe flying according to a UAV flight plan, as is depicted by FIG. 2, thendetect and avoid an unknown aircraft, as is depicted in FIG. 3.Additionally, any time that UAV 100 determines that it needs to changecourse, UAV 100 may transmit an alert to the ground control stationindicating the course change. In general, UAV 100 preferably appliesmulti-modal navigation logic, using input from multiple sources, to makedeterminations of how to conduct its mission.

FIGS. 5, 6, and 7 depict flow charts of methods in accordance withexemplary embodiments of the present invention by representingrespective sequences of steps or events. However, these steps or eventsmay occur in a different order, and fewer or more steps or events mayoccur without departing from the scope of the embodiments. Moreover, themethods depicted in these flow charts may be combined with one anotherwholly or in part, to form additional embodiments that are also withinthe scope of this invention.

FIG. 5 depicts a flow chart of method 500. Method 500 provides a meansto adjust a UAV flight plan based on input from a camera. At step 510, afirst UAV flight plan is calculated to avoid at least one flightcorridor and at least one flight path. The flight corridor may be, forexample, a commercial flight corridor and may comprise one or more of awaypoint, a vector, a width centered upon the vector, and altituderange, and a time range. The flight path may be a flight path of a UAVor of a manned aircraft, and may also comprise one or more of awaypoint, a vector, a width centered upon the vector, and altituderange, and a time range.

At step 520, the UAV flies according to the first UAV flight plan. Atstep 530, based on the first UAV flight plan and input from a camera, asecond UAV flight plan is calculated. The input from the camera may be,for example, navigational signals in visible light frequencies,navigational signals in infrared light frequencies, or other indicationsof a moving or stationary obstacle. Consequently, at step 540, the UAVflies according to the second flight plan. In particular, if the inputfrom the camera indicates an obstacle, the second flight plan preferablyavoids the obstacle. Method 500 may be carried out entirely by a UAV,such as UAV 100, or by a UAV in conjunction with a ground controlstation.

FIG. 6 depicts a flow chart of method 600. Method 600 may take placeduring or after the carrying out of method 500. At step 610, an acousticsensor is used to detect an unknown aircraft. This unknown aircraft islikely to be in the vicinity of the UAV. At step 620, based on aprevious UAV flight plan, such as the first UAV flight plan or thesecond UAV plan from method 500, a new UAV flight plan is calculated.The new UAV first plan preferably avoids the unknown aircraft, as wellas any other obstacles, and may involve the UAV changing speed,direction, and/or altitude with respect to the previous UAV flight plan.Consequently, at step 630, the UAV flies according to the new UAV flightplan.

FIG. 7 depicts a flow chart of method 700. Method 700 may take placeduring or after the carrying out of method 500. At step 710, a UAV, suchas UAV 100, and a friendly UAV share information with one another via awireless network. The wireless network may be a point to point networkbetween the UAV and the friendly UAV or a broadcast network.Transmissions between the UAV and the friendly UAV may pass back andforth over this network and may contain information regarding one ormore flight corridors, flight plans, flight paths, obstacles, or unknownaircraft. At step 720, based on a previous UAV flight plan and theinformation shared by the friendly UAV, a new UAV flight plan iscalculated. This new flight plan preferably avoids the one or moreflight corridors, flight plans, flight paths, obstacles, or unknownaircraft that the UAV learned about from the friendly UAV. Consequently,at step 730, the UAV flies according to the new UAV flight plan.

FIG. 8 is a simplified block diagram exemplifying UAV 100, andillustrating some of the functional components that would likely befound in a UAV arranged to operate in accordance with the embodimentsherein. Although not shown in FIG. 8, the UAV may be a ducted fan UAVcapable of vertical takeoff and landing. However, other UAV designs maybe used.

Example UAV 100 preferably includes a processor 802, a memory 804, acommunication interface 806, and one or more sensors 808, all of whichmay be coupled by a system bus 810 or a similar mechanism. Processor 802preferably includes one or more CPUs, such as one or more generalpurpose processors and/or one or more dedicated processors (e.g.,application specific integrated circuits (ASICs), field programmablegate arrays (FPGAs), or digital signal processors (DSPs), etc.) Memory804, in turn, may comprise volatile and/or non-volatile memory and canbe integrated in whole or in part with processor 802.

Memory 804 preferably holds program instructions executable by processor802, and data that is manipulated by these instructions to carry outvarious logic functions described herein. (Alternatively, the logicfunctions can be defined by hardware, firmware, and/or any combinationof hardware, firmware and software.)

Communication interface 806 may take the form of a wireless link, andoperate according to protocols based on, for example, OFDM, frequencyhopping, or CDMA. However, other forms of physical layer connections andother types of standard or proprietary communication protocols may beused over communication interface 806. Furthermore, communicationinterface 806 may comprise multiple physical interfaces (e.g., multiplewireless transceivers). Regardless of the exact means of implementation,communication interface 806 is preferably capable of transmitting andreceiving information between UAV 100 and one or more other manned orunmanned aircraft, and/or between UAV 100 and one or more ground controlstations.

Sensors 808 facilitate the gathering of environmental information in thevicinity of UAV 100. Sensors 808 may comprise multiple types of sensingdevices, such as video cameras acoustic sensors, motion sensors, heatsensors, wind sensors, RADAR, LADAR, EO sensors, IR sensors, and/orEO/IR sensors. Sensors 808 preferably can detect stationary or movingobjects and obstacles based the visible and infrared light spectra, aswell as based on such an object's acoustic emanations.

By way of example, memory 804 may comprise data representing at leastone flight path of a different aircraft and data representing at leastone flight corridor. Furthermore, memory 804 may comprise programinstructions executable by the processor to calculate a first UAV flightplan to avoid the at least one flight plan and the at least one flightcorridor and to store the first UAV flight plan in the memory, programinstructions executable by the processor for the UAV to fly according tothe first UAV flight plan, program instructions executable by theprocessor to calculate a second UAV flight plan based on the first UAVflight plan and input from a camera, and program instructions executableby the processor for the UAV to fly according to the second UAV flightplan.

Additionally, memory 804 may comprise program instructions executable bythe processor to calculate a third UAV flight plan based on the secondUAV flight plan and input from an acoustic sensor and programinstructions executable by the processor for the UAV to fly according tothe third UAV flight plan.

Furthermore, memory 804 may comprise program instructions executable bythe processor to receive flight plan information from other UAVs or aground control station via the wireless network interface, programinstructions executable by the processor to calculate a third UAV flightplan based on the second UAV flight plan and the received flight planinformation, and program instructions executable by the processor forthe UAV to fly according to the third UAV flight plan.

Similar to the basic block diagram shown in FIG. 8, a ground controlstation may also comprise a processor, memory, and a communicationsinterface linked by a bus. In an alternate embodiment, the multi-modalnavigation logic used by a UAV, such as UAV 100, may be distributedbetween the UAV and such a ground control station. Thus, somenavigational decisions may be made by the UAV, while other navigationaldecisions are made by the ground control station, or some combination ofthe UAV and the ground control station. Furthermore, such a UAV may bein contact with multiple ground control stations, and sharedecision-making capabilities with one or more of these ground controlstations.

Exemplary embodiments of the present invention have been describedabove. Those skilled in the art will understand, however, that changesand modifications may be made to these embodiments without departingfrom the true scope and spirit of the invention, which is defined by theclaims.

1. A method for navigation, wherein an unmanned aerial vehicle (UAV) is equipped with data representing at least one flight corridor, data representing at least one flight path, and a camera, the method comprising: calculating a first UAV flight plan to avoid the at least one flight corridor and the at least one flight path; flying the UAV according to the first UAV flight plan; calculating a second UAV flight plan based on the first UAV flight plan and input from the camera; and flying the UAV according to the second UAV flight plan.
 2. The method of claim 1, wherein the at least one flight corridor comprises a commercial aircraft flight corridor.
 3. The method of claim 1, wherein the flight corridor comprises at least one of a waypoint, a vector, a width centered upon the vector, an altitude range, and a time range.
 4. The method of claim 1, wherein the at least one flight path comprises a UAV flight path.
 5. The method of claim 1, wherein the flight path comprises at least one of a waypoint, a vector, a width centered upon the vector, an altitude range, and a time range.
 6. The method of claim 1, wherein the camera detects navigational signals in the range of visible light frequencies.
 7. The method of claim 1, wherein the camera detects navigational signals in the range of infrared light frequencies.
 8. The method of claim 1, wherein the input from the camera indicates an obstacle to the first UAV flight plan, and wherein the second UAV flight plan avoids the obstacle.
 9. The method of claim 1, wherein the UAV is further equipped with an acoustic sensor, the method further comprising: the acoustic sensor detecting an unknown aircraft; and calculating a third UAV flight plan, based on the second UAV flight plan, to further avoid the unknown aircraft; and flying the UAV according to the third UAV flight plan.
 10. The method of claim 9, wherein calculating a third UAV flight plan comprises at least one of the UAV changing direction and the UAV changing speed compared to the second UAV flight plan.
 11. The method of claim 1, wherein the UAV includes a wireless network interface, and wherein the UAV is deployed in a theatre containing at least one friendly UAV, the method comprising: the UAV and the friendly UAV sharing information with one another via a wireless network; calculating a third UAV flight plan, based on the second UAV flight plan and the information shared by the friendly UAV; and flying the UAV according to the third UAV flight plan.
 12. The method of claim 11, wherein the shared information is a flight plan.
 13. The method of claim 11, wherein the wireless network is a point to point network between the UAV and the friendly UAV.
 14. The method of claim 11, wherein the wireless network is a broadcast network.
 15. The method of claim 1, wherein the UAV includes a wireless network interface, and wherein the UAV is capable of communicating with at least one ground control station, the method comprising: the ground control station transmitting information to the UAV; the UAV and the ground control station calculating a third UAV flight plan, based on the second UAV flight plan and the information transmitted by the ground control station; and flying the UAV according to the third UAV flight plan.
 16. An unmanned aerial vehicle (UAV) comprising: a processor; a camera; and a memory containing: data representing at least one flight path of a different aircraft; data representing at least one flight corridor; program instructions executable by the processor to calculate a first UAV flight plan to avoid the at least one flight plan and the at least one flight corridor and to store the first UAV flight plan in the memory; program instructions executable by the processor for the UAV to fly according to the first UAV flight plan; program instructions executable by the processor to calculate a second UAV flight plan based on the first UAV flight plan and input from the camera; and program instructions executable by the processor for the UAV to fly according to the second UAV flight plan.
 17. The UAV of claim 16, further comprising: an acoustic sensor capable of detecting an unknown aircraft; and the memory further comprising: program instructions executable by the processor to calculate a third UAV flight plan based on the second UAV flight plan and input from the acoustic sensor; and program instructions executable by the processor for the UAV to fly according to the third UAV flight plan.
 18. The UAV of claim 16, further comprising: a wireless network interface; and the memory further comprising: program instructions executable by the processor to receive flight plan information from other UAVs via the wireless network interface; program instructions executable by the processor to calculate a third UAV flight plan based on the second UAV flight plan and the received flight plan information; and program instructions executable by the processor for the UAV to fly according to the third UAV flight plan.
 19. The UAV of claim 16, wherein the UAV is a ducted fan UAV.
 20. The UAV of claim 19, wherein the UAV is capable of vertical takeoff and landing. 